Wound treatment apparatus

ABSTRACT

A control unit is adapted for use with a vacuum wound bandage. The control unit has a canister to collect waste material from the vacuum wound bandage, a fluid source to irrigate the wound, and a door to at least partially cover the fluid source.

RELATED APPLICATION

[0001] This disclosure is a continuation-in-part of U.S. applicationSer. No. 09/725,666, which was filed Nov. 29, 2000 and which is herebyincorporated by reference herein.

TECHNICAL FIELD

[0002] The present disclosure relates to wound treatment apparatus foruse with vacuum bandages of the type that dispenses fluid to a wound anddraws fluid away from the wound.

BACKGROUND AND SUMMARY

[0003] Medical professionals, such as nurses and doctors, routinelytreat patients having surface wounds of varying size, shape, andseverity. It is known that controlling the topical atmosphere adjacent awound can enhance the healing process. For example, by applyingmedicinal agents or even water over a wound, dirt and bacteria areeither killed or washed away, thereby promoting healing. In addition,applying a negative pressure or vacuum to a wound draws out exudate,which might contain dirt and bacteria, from the wound to further promotehealing.

[0004] Conventional treatment of a surface wound involves placement of apacking or dressing material, such as cotton, gauze, or otherbandage-like material directly in contact with the patient's wound.Often there is a need to change the dressing material frequently becauseit becomes saturated with exudate discharged from the wound. Somedressings include an apparatus attached thereto for applying a vacuumthrough the bandage to the wound to draw exudate and promote healing.

[0005] According to the present disclosure, a control unit is adaptedfor use with a vacuum wound bandage. The control unit comprises acontrol module to provide a negative pressure through the vacuum woundbandage and a canister having an interior region to collect wastematerial from the vacuum wound bandage and a latch to couple thecanister to the control module. The latch extends through the interiorregion. Illustratively, the latch is operable to move the canister intosealing engagement with the control module. Further illustratively, thecanister has a sleeve positioned within the interior region, and aportion of the latch is positioned within the sleeve.

[0006] According to another aspect of the disclosure, the control unitcomprises a vacuum source to provide a desired negative pressure throughthe vacuum wound bandage to treat the wound, a pressure sensor, and acanister. The canister has a chamber to collect waste material from thevacuum bandage, an inlet port to introduce waste material from thevacuum bandage into the chamber, an outlet port to communicate with thechamber and the vacuum source, and a pressure port to communicate withthe chamber and the pressure sensor. The pressure port is positioned toallow the pressure sensor to sense the pressure within the chamber whenthe waste material within the chamber at least partially occludes theoutlet port so as to prohibit the vacuum source from providing thedesired negative pressure within the chamber.

[0007] According to another aspect of the disclosure, the control unitcomprises a fluid source to irrigate the wound, a housing carrying thevacuum source and the fluid source, and a door movable relative to thehousing between an opened position uncovering the fluid source and aclosed position at least partially covering the fluid source. Thecontrol unit further comprises a latch coupled to the door for movementrelative to the door between a latched position blocking movement of thedoor from its closed position to its opened position and a releaseposition allowing the door to move between its closed position and itsopened position. According to another aspect of the disclosure, the doorhas a mount supporting the fluid source.

[0008] Additional features and advantages of the apparatus will becomeapparent to those skilled in the art upon consideration of the followingdetailed descriptions exemplifying the best mode of carrying out theapparatus as presently perceived.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The illustrative apparatus will be described hereinafter withreference to the attached drawings, which are given as non-limitingexamples only, in which:

[0010]FIG. 1 is a perspective view of a wound treatment apparatuscoupled to a bandage attached to a patient;

[0011]FIG. 2 is a block diagram of the wound treatment apparatus of FIG.1;

[0012]FIG. 3 is a schematic diagram of the wound treatment apparatus ofFIG. 1;

[0013]FIG. 4 is a side cross-sectional view of the wound treatmentapparatus along the lines A-A of FIG. 1;

[0014]FIG. 5 is a schematic block diagram of the vacuum evacuatingsubsystem of the wound treatment apparatus of FIG. 1;

[0015]FIG. 6 is a cross-sectional view of a waste disposal canister ofthe wound treatment apparatus along the lines B-B of FIG. 1;

[0016]FIG. 7 is a partially exploded perspective view of the woundtreatment apparatus of FIG. 1 with the waste canisters removed;

[0017]FIG. 8 is a perspective view of another embodiment of the woundtreatment apparatus;

[0018]FIG. 9 is a side diagrammatic view of the vacuum bandage andportions of the wound treatment apparatus of FIG. 1;

[0019]FIG. 10 is a perspective view of the wound treatment apparatus ofFIG. 1 with the waste cannister removed;

[0020]FIG. 11 is a front elevational view of a waste canister;

[0021]FIG. 12 is a side elevational view of the waste canister of FIG.11; and

[0022]FIG. 13 is a top view of the waste canister of FIG. 11.

[0023]FIG. 14 is a perspective view of another wound treatment apparatusshowing a pair of canisters arranged for insertion into respectivereceptacles formed in the sides of a housing of a control unit andshowing a fluid source arranged for insertion into a receptacle formedin the front of the housing;

[0024]FIG. 15 is an enlarged elevation view of a latch for a door of thewound treatment apparatus of FIG. 14 showing the latch in a releaseposition;

[0025]FIG. 16 is a view similar to FIG. 15 showing the latch in alatched position;

[0026]FIG. 17 is a fragmentary sectional view showing a syringe having aflange received by grooves of the door and the housing to retain abarrel of the syringe in place;

[0027]FIG. 18 is a perspective view of the rear of a control unit of thewound treatment apparatus of FIG. 14 showing a carrying handle at thetop of the control unit and a mounting bracket on a rear wall of thecontrol unit;

[0028]FIG. 19 is a perspective view of the rear of the control unit ofFIG. 18 with a rear wall removed;

[0029]FIG. 20 is an exploded perspective view of a waste collectioncanister of the control unit;

[0030]FIG. 21 is a fragmentary perspective view of a portion of thecanister of FIG. 20 and a portion of a receptacle of the housing inwhich the canister is received;

[0031]FIG. 22 is a side sectional view of the canister partiallyinserted into the receptacle;

[0032]FIG. 23 is a side sectional view similar to FIG. 22 of thecanister installed within the receptacle;

[0033]FIG. 24 is an enlarged elevation view of the interface between thelatch and a wall of the receptacle showing lugs of the latch alignedwith lug-receiving spaces of an aperture formed in the receptacle wall;

[0034]FIG. 25 is an enlarged elevation view, similar to FIG. 24, showingthe lugs of the latch misaligned with the lug-receiving spaces of theaperture to retain the canister in the receptacle;

[0035]FIG. 26 is a sectional view taken along line 26-26 of FIG. 25showing engagement between the lugs and the receptacle wall;

[0036]FIG. 27 is a diagrammatic view of portions of the wound treatmentapparatus of FIG. 14;

[0037]FIG. 28 is a diagrammatic view of a three-chambered muffler.

[0038] Corresponding reference characters indicate corresponding partsthroughout the several views. The exemplification set out hereinillustrates several embodiments of the apparatus, and suchexemplification is not to be construed as limiting the scope of thisdisclosure in any manner.

DETAILED DESCRIPTION OF THE DRAWINGS

[0039] An embodiment of wound treatment apparatus 2 is shown in FIG. 1.Wound treatment apparatus 2 comprises a central unit housing 4, havingwound treatment systems 6, 8 appended to each side of housing 4. A userinterface 10 is shown positioned between each treatment system 6, 8.Central unit housing 4 is configured to be a portable unit allowing acaregiver to move housing 4 to wherever the patient is located and toclose proximity to the wound or wounds. Housing 4 is shown having ahandle portion 12 to assist the caregiver in moving housing 4. FIG. 1also shows wound treatment system 6 coupled to a bandage 14 attached toa patient's leg 16. Dispensing and evacuating tubes 18, 20 are coupledto both bandage 14 and system 6. Specifically, dispensing tube 18 iscoupled to a luer-lok port 22 extending from syringe 24. Syringe 24 isfilled with a fluid, typically saline, that empties through tube 18 andinto bandage 14, and ultimately onto a wound 300 positioned underbandage 14. (See also FIG. 9.) After contacting wound 300, the fluid andexudate from wound 300 are drawn from bandage 14 through evacuating tube20 and into a waste canister 26 where it is collected. It iscontemplated that the canister 26 can be discarded when filled andreplaced with a new canister 26.

[0040] Apparatus 2 comprises a second system 8 on the opposite side ofhousing 4 from system 6. This configuration allows two wounds to betreated simultaneously with separate bandages, yet, under the control ofa single housing 4. Second bandage 15, as part of system 8, is coupledto dispensing and evacuating tubes 28, 30, respectively, to perform thesame functions as described for system 6. (See FIG. 2.) User interface10 is provided to allow the caregiver to control either or both systems6, 8, to dispense fluid from either or both syringes 24, 224, and toevacuate from either or both bandages 14, 15. It is contemplated thateach wound treatment system 6, 8 will work independent of each other,thus, allowing the caregiver flexibility to apply an appropriate and,yet, possibly different level of treatment to each wound.

[0041] The arrangement of systems 6, 8 relative to user interface 10 onhousing 4 allows convenient interaction between systems 6, 8 and thecaregiver. For example, syringes 24, 224 are conveniently positioned onopposite sides of user interface 10. Each syringe is partially coveredby doors 32, 33 on the front of housing 4. Each door 32, 33 swingsoutwardly about hinges 34, 36, allowing syringes 24, 224 to be removedand replaced. Similarly, waste canisters 26, 27 are each positioned in acavity 9 provided on each side of housing 4. (See FIG. 7.) Each canister26, 27 includes a grip portion 40 for convenient removal andreplacement. Canisters 26, 27 are illustratively secured into eachcavity by a friction fit. (See FIG. 6.) It is appreciated, however, thatsyringes 24, 224 can be secured to other locations on housing 4.

[0042] The portability of apparatus 2 allows a caregiver to position itnear the patient in preparation for treatment wherever the patient islocated. To prepare apparatus 2 for treatment, the caregiver securessyringes 24, 224, which contain fluid, to apparatus 2 in a mannerdescribed in greater detail below. The caregiver then couples tube 18 toport 22 and bandage 14, and tube 20 to bandage 14 and waste canister 26,for treatment of one wound. The caregiver then couples tube 28 to port222 and bandage 15, and tube 21 to bandage 15 and waste canister 27, fortreatment of a second wound. (See also FIG. 2.) The caregiver, throughthe use of user interface 10 can treat the patient by selectivelyirrigating the wounds with fluid and drawing exudate and the fluid fromthe wounds.

[0043] A diagram depicting how wound apparatus 2 operates is shown inFIG. 2. A controller 50 is provided in housing 4 and is an electroniccontrol unit that controls apparatus 2. Controller 50 receives userinput from and provides feedback to user interface 10 through lines 52,54, respectively. It is contemplated that controller 50 will processinformation from both systems 6, 8, and provide appropriate andindependent input to each system. Controller 50 also monitors the statusof all various sensors, and provides input for the valves and motors, asdiscussed in further detail herein. Illustratively, user interface 10 iscomposed of a conventional graphic liquid crystal display (LCD) and amembrane switch panel.

[0044] A power supply 56 provides power to controller 50 and all theattendant systems in housing 4. Power supply 56 can be a conventionalexternal wall socket supply (not shown), or be a battery pack supply(also not shown), or even be variations of both (e.g., a wall socketsupply with a battery pack supply). Illustratively, power supply 56 is amedical grade power supply providing an output of about 65-watts and avoltage of about 12VDC. It is contemplated that the power supply can beconfigured for 120V/60 Hz or 220-240V/50 Hz depending on whether housing4 is used in America or Europe. Illustratively, the battery powerprovides the device with power to operate for about 60 minutes withoutconnection to an external power source. It is further contemplated thatthe batteries can be rechargeable, and store energy when the device isconnected to an external wall socket.

[0045] An attitude sensor 58 is provided in communication withcontroller 50 through line 60. Attitude sensor 58 is, illustratively, atilt switch which provides feedback to controller 50. If the switch is,illustratively, in the closed position, controller 50 will continue tooperate, but if the switch opens, controller will shut systems 6, 8down. For example, sensor 58 disables systems 6, 8 if housing 4 tilts ator greater than a predetermined amount, such as 45° from vertical in anydirection.

[0046] It is contemplated that controller 50, user interface 10, powersupply 56, and attitude sensor 58 are all common to and all operate withboth systems 6, 8. Each system 6, 8 further comprises fluid dispensingand vacuum evacuating subsystems 62, 64 and 66, 68. Fluid dispensingsub-system 62 comprises a syringe 24 having a plunger 70. (See also FIG.4.) Syringe 24 is, illustratively, a standard 60-ml medical syringeutilizing a luer-lok port 22. Plunger 70 is a conventional plunger thatextends into syringe 24 to dispense fluid through luer-lok port 22. Asyringe drive motor 72 is, illustratively, a 12VDC brushless electricmotor or stepper motor configured to provide rotational energy to asyringe drive 74. (See FIG. 4.) When a signal is sent from controller 50along line 76 to syringe drive motor 72, motor 22 applies torque andangular velocity to syringe drive 74 which is, illustratively, a powerscrew 322. (See also FIG. 4.) Power screw 322 translates rotationalmovement of the syringe drive motor 72 into translational movement. Thedrive has a guide 80 to limit a plunger interface 78 to motion along oneaxis. In the illustrated embodiment, syringe drive 72 provides about5.25 inches (13.3 cm) of travel of plunger interface 78, indicated byreference numeral 82, to evacuate the fluid contained in syringe 24.(See also FIG. 4.) Furthermore, syringe drive motor 72 and syringe drive74, as a system, provide about 27 pounds of linear force at a velocityof 1.45 inches (3.7 cm) per second to the plunger interface 78. Theresulting force created by the fluid exiting syringe 24 creates,illustratively, 4-PSIG to 6-PSIG positive pressure at wound 300.

[0047] A syringe home sensor 84 receives information from plungerinterface 78, and provides feedback to controller 50 when syringecapture mechanism 88 reaches its home position 79. A syringe full travelsensor 86 determines when syringe 24 is fully evacuated by sensing whenplunger interface 78 has reached full travel. After sensor 86 has beenactivated, controller 50 resets plunger interface 78 to home position 79once syringe 24 is removed.

[0048] Syringe capture mechanism 88 holds syringe 24 in place when thecaregiver places syringe 24 in apparatus 2. (See also FIG. 4.) Capturemechanism 88 is also configured to allow the caregiver to releasesyringe 24 from apparatus 2 when it is empty. Capture mechanism 88further includes a syringe sensor 90 that provides feedback tocontroller 50 through line 92 when syringe 24 is properly held incapture mechanism 88. Controller 50 prevents system 6 from operating ifsensor 90 does not detect syringe 50 being properly held in capturemechanism 88.

[0049] Connectors 94, 96 are provided at opposed ends of dispensing tube18. Either one or both connectors 94, 96, when closed, block flow fromsyringe 24 to bandage 14. Such connectors 94, 96 allow the patient to bedisconnected from apparatus 2 without having to remove bandage 14 oreven shut apparatus 2 down.

[0050] A manual port 98 is also attached to dispensing tube 18 by anauxiliary tube 100. Port 98 permits the caregiver to attach a dispensingcontainer to the system to manually dispense fluid into bandage 14. Itis appreciated, however, that port 98 is configured to be closed whileno syringe is attached to maintain a closed system.

[0051] The syringe and drive are illustrated as one approach forproviding a fluid source and a drive for irrigating a wound bed. It willbe appreciated that containers other than syringes may be operated by adrive to expel irrigation fluid toward a wound surface. For example, anytype of container of fluid may be squeezed or reduced in volume by adrive mechanism to expel fluid. Also, as discussed in connection withFIG. 8, a container may be held at an elevated position to provide headpressure for irrigation fluid.

[0052] Connectors 104, 106, similar to connectors 94, 96, are providedat opposed ends of evacuating tube 20. Either one or both connectors104, 106, when closed, block flow from bandage 14 to waste canister 26.Such connectors 104, 106 also allow the patient to be disconnected fromapparatus 2 without having to remove bandage 14 or having to shut downapparatus 2.

[0053] Waste canister sensors 116, 118 are engaged when waste container26 is properly seated in apparatus 2. This prevents apparatus 2 fromoperating without canister 26 seated properly in apparatus 2. Asdepicted in FIG. 2, both sensors 116, 118 provide feedback to controller50 through lines 120, 122, confirming to the caregiver that canister 26is seated properly in apparatus 2.

[0054] In the illustrated embodiment, waste canister 26 is a disposableunit that “snaps into” side portion 38 of housing 4. (See also FIGS. 1and 6.) Illustratively, canister 26 includes a window (not shown) toallow monitoring of the fluids. Illustratively, the fluid capacity ofcanister 26 is about 500-ml.

[0055] The illustrated embodiment of waste canister 26 further includesa hydrophobic filter 108 that is in communication with both evacuatingtube 20 and vacuum pump 110. (See also FIG. 6.) Such filter 108 isconfigured to allow air, but not liquid, to pass. Accordingly, as fluidis drawn into canister 26, fluid is deposited into waste canister 26while the vacuum continues through filter 108 and pump 110.Illustratively, filter 108 is a 1.0-micron hydrophobic filter fixed intorear wall 407 of canister 26. (See FIG. 6.) Hydrophobic filter 108 alsoserves as a canister full mechanism 114 or valve that shuts off thevacuum supply to the canister 26 when the fluid level exceeds the “full”level 420. Because hydrophobic filter 108 prevents fluid from passing,once fluid covers filter 108, vacuum is prevented from passing as well.The absence of any vacuum in the system will cause the system to shutdown.

[0056] Vacuum pump 110 creates the negative pressure that is presentthrough canister 26. For monitoring and controlling such negativepressure, the vacuum is present through several devices, including avacuum pressure transducer 124. Transducer 124 is coupled to line 128,extending from canister 26. (See FIG. 5.) Transducer 124 measures thenegative pressure that is present through canister 26. Transducer 124then provides feedback to controller 50 through line 128. Controller 50monitors the negative pressure by comparing the measured value fromtransducer 124 with the caregiver-defined value entered into controller50 through user interface 10.

[0057] A proportional valve 130 is connected to line 126, through whichthe negative pressure is present, and which comprises a flow orifice132. (See also FIG. 5.) Flow orifice 132 selectively dilates orconstricts, thereby controlling the negative pressure level throughsub-system 66. Specifically, controller 50 provides a signal input toproportional valve 130 based on the level of the vacuum pressuredetermined from feedback of transducer 124 and comparing that level tothe caregiver-defined level. Orifice 132 then dilates or constricts, asnecessary, to produce the appropriate level of negative pressure.Illustratively, proportional valve 130 is fully constricted or closedwhen receiving no signal from controller 50, and dilates or opens toallow an illustrative maximum of two liters per minute at 250-mmHg(4.83-PSIG) vacuum when the proper signal from controller 50 is applied.

[0058] A vacuum regulator 134 is provided in line 126 betweenproportional valve 130 and pump 110 as a mechanical limit control forpump 110. Regulator 134 mechanically establishes a maximum level ofnegative pressure that is present in the system. Thus, vacuum pump 110will not physically be able to draw a vacuum from bandage 14 beyond themaximum pressure. Illustratively, such maximum negative pressure orvacuum is 250-mmHg (4.83-PSIG). In addition, when proportional valve130, pursuant to a signal from controller 50, creates a negativepressure less than the maximum negative pressure level, a port 136,coupled to regulator 134, opens so that pump 110 can draw more air tomaintain a sufficient flow through pump 110, to prevent it from becomingdamaged. A first air filter 137 is illustratively associated with port136, between port 136 and pump 110, to filter particulates from the airprior to reaching pump 110. Illustratively, filter 137 is constructed ofglass microfibers with a filtration rating of 25 microns. A secondfilter 139 is associated with pump 110 and an outlet 141. Filter 139serves as an exhaust muffler for the air evacuated from pump 110.

[0059] Vacuum pump 110 is, illustratively, a diaphragm-type compressorthat flows about two liters per minute at 250-mmHg (4.83-PSIG) vacuum.Illustratively, vacuum pump 110 is mounted on the end of a single 12VDCbrushless motor 138 to drive the pump. It is appreciated, however, thatpump 110 can be of any other configuration, and mounted in any manner,so long as it draws a desired negative pressure through system 6. It isalso contemplated that a vacuum pump external to the housing 4 may be apart of the control system. For example, most medical facilities havevacuum ports near where patients are treated, each of which is served bya system vacuum (suction) pump. It is contemplated, therefore, that thepump 110 in the housing 4 may be an appropriate fitting which is, inturn, connected to a facility vacuum pump to provide a vacuum source tothe control system.

[0060] It is contemplated that port 136, filters 137, 139, electricmotor 138, vacuum pump 110, and vacuum regulator 134 are all housed in asound chamber 140. Illustratively, the interior of sound chamber 140 islined with a damping foil like the 3M Company's damping foil number2552, for example. Sound chamber 140 dampens vibration energy producedby these components, as well as assists in dissipating heat theygenerated.

[0061] As previously indicated, it is contemplated that controller 50,user interface 10, power supply 56, and attitude sensor 58 are commonto, and operate with, both fluid dispensing and vacuum evacuatingsub-systems 62, 64 and 66, 68. Providing a second independently operableset of sub-systems 64, 68 allows the caregiver to treat two wounds usinga single apparatus 2. Accordingly, second fluid dispensing andevacuating sub-systems 64, 68 also shown in FIG. 2, comprise identicalcomponents as discussed regarding sub-systems 62, 66 and are labeled ina corresponding manner. For example, syringe motor drive 72 insub-system 62 is identified as syringe motor drive 172 in sub-system 64,and a vacuum pump 110 in sub-system 66 is identified as vacuum pump 210in sub-system 68.

[0062] A schematic diagram of a portion of wound treatment apparatus 2is shown in FIG. 3. Each system 6 and 8 is configured to operate in thesame manner. Specifically, FIG. 3 depicts the operation of system 6.Movement of plunger 70 into syringe 24 causes fluid stored in syringe 24to exit into tube 18 and into bandage 314 where it drains throughorifices 302 onto wound 300. Vacuum 110 applies a negative pressurethrough waste canister 26 and bandage 314. Fluid and exudate are thendrawn from wound 300 out through tube 20 and into canister 26. Thehydrophobic filter 108, discussed in connection with FIG. 2, allows thevacuum to pass through waste canister 26, yet, prevents any of the fluidfrom escaping, and depositing the fluid into pump 110.

[0063] The mechanism for moving plunger 70 into syringe 24, part offluid dispensing sub-system 62, is shown in cross-sectional form in FIG.4. The illustrated embodiment includes sub-system 62 positioned withinhousing 4. Specifically, a bracket frame 310 serves as the skeletalstructure for sub-system 62. Bracket 310 includes a base portion 312with an upwardly extending structural member 314 appending from one endthereof. A support portion 316 extends outwardly from member 314, and issuperposed above base portion 312. Extending from support portion 316 issyringe bracket 318. Syringe capture mechanism 88 is formed in bracket318, and is configured to receive syringe 24, as previously discussed.Bracket 318 and capture mechanism 88 are configured to suspend syringe24 with luer-lok port 22 directed upwardly. It is contemplated thatcapture mechanism 88 secures syringe 24 to bracket 318 by other means,including being friction-fitted, or secured with clips or bolts. To moveplunger 70, syringe drive 74 and plunger interface 78 are coupled toframe 310. Plunger interface 78 captures plunger 70 and provides upwardlinear motion to evacuate syringe 24. Interface 78 provides a releasemechanism for plunger 70 to remove syringe 24 at any position in thestroke.

[0064] Syringe drive 74 comprises syringe drive motor 72 and power screw322. Power screw 322 is disposed through an aperture 324 in supportportion 316, and is rotatably coupled to motor 72. It is appreciatedthat motor 72 can be a stepper or electric motor, for example. The lowerend 326 of power screw 322 is positioned within a bearing cavity 328within which power screw 322 rotates. Spaced in parallel to power screw322 is guide 80. Guide 80 is received in an aperture 330, also disposedin support portion 316 at its upper end 332, and is received in cavity334 at its lower end 336. Plunger interface 78 is configured to receivecap 338 of plunger 70, and is coupled to a dual coupler 340. Dualcoupler 340 comprises two blocks 342, 344, each having bores 346, 348disposed, respectively, there through. In the illustrated embodiment,bore 346 has a smooth surface and is configured to receive guide 80. Incontrast, bore 348 has a threaded surface and is configured to cooperatewith threads on power screw 322. Coupler 340 is movable upwardly anddownwardly in directions 350, 352. A hatched outline version of coupling340, indicated by reference numeral 354, is shown depicting plungerinterface 78 and plunger 70 moving upwardly in direction 350. As shownin FIG. 4, as plunger 70 is moved upwardly, head 356 is also movedupwardly, reducing the available space in syringe 24, thus, displacingany fluid in syringe 24 out of luer-lock port 22, thereby dispensing thefluid into tube 18 and into bandage 14. The movement of cap 356 isdepicted by the position of cap 356 in hatched lines moved to an upperposition indicated by reference numeral 358.

[0065] A cross-sectional view of waste canister 26 located in cavity 9on side 38 of housing 4 is shown in FIG. 6. Tube 20 is connected to acheck-valve assembly 400 coupled to recess 402 disposed in the frontwall 405 of canister 26. Check valve 400 is configured to allow fluidand exudate from bandage 14 to enter canister 26 and deposit in holdingspace 404 within canister 26, yet prevent any fluid already in space 404from exiting through valve 400. Check valve 400, thus prevents fluidfrom escaping when tube 20 is disengaged from valve 400. In addition,canister 26 can be discarded without any fluid escaping. Hydrophobicfilter 108 is located on the rear wall 407 of canister 26. A liquidsolidifier 29 is provided in space 404 to decease the fluidity of theexudate. This is a safety measure to lessen the chance of splashing orrun-off if canister 26 (or 27) is opened or broken.

[0066] Filter 108 in canister 26 is shown having an inlet 410 providedin space 404 and an outlet 412 coupled to a connector 416 with a barrierof hydrophobic material 414 provided there between. As previouslydiscussed, the hydrophobic material allows the vacuum to pass throughinlet 410 and outlet 412, yet prevents any fluid from passing. Similarto check valve 400, hydrophobic filter 108 too prevents any fluid fromescaping even when canister 26 is removed from housing 4. Outlet 412 offilter 108 is in communication with connector 416. Connector 416 isconfigured to receive and seal outlet 412 when canister is positioned incavity 9. Connector 416 is in communication with line 126 and ultimatelywith pump 110.

[0067] In the illustrated embodiment, hydrophobic filter 108 serves asboth the canister full mechanism 114 that shuts off the vacuum supply tothe canister 26 when the fluid level exceeds the “full” level asindicated by reference numeral 420. When the fluid level is below inlet410, as indicated by reference numeral 422, fluid continues to enterspace 404 through valve 400. When the fluid level 420 is above inlet410, the fluid is acting as an air block. Fluid cannot pass throughfilter 108, but because the fluid level is above inlet 410, air cannotpass through either. This causes a dramatic pressure drop (vacuumincrease) through line 126. Vacuum pressure transducer 124 is coupled toline 126 measuring the negative pressure passing through canister 26, aspreviously discussed. If such a dramatic pressure drop occurs,transducer 124 will provide such data to controller 50 through line 128.Controller 50 will then know to shut the system down until the fullcanister is replaced with either an empty or only a partially fullcanister.

[0068] Another illustrative embodiment of a wound treatment apparatus isshown in FIG. 8 and is indicated by reference numeral 3. Apparatus 3operates in a similar manner as apparatus 2, with the exception of theuse of two “intravenousstyle” fluid bags 510, 512 suspended abovehousing 4 to dispense the fluid. In this illustrated embodiment, posts514, 516 with hooks 518, 520 extend upwardly of apparatus 3 from behinddoors 32, 33. It will be appreciated that the posts 514, 516 may beextensible to elevate the bags 510, 512 to selected heights to provideselected pressures for irrigation. A dispensing tube 18 extends fromeach bag 510, 512 at one end and couples to each bandage. Gravityassists in moving fluid through tubes 18 and into the bandages. A tubeclip 522 is coupled to each tube 18 and configured to pinch and closetube allowing the caregiver to selectively prevent fluid from dispensinginto bandages.

[0069] Illustrative vacuum bandage 314 of FIG. 3 is designed to providea protective environment around wound 300. Illustratively, such bandageslast for up to 7 days without having to be replaced. Bandage 314includes rinse and drain orifices (not shown) within the body of bandage314 that communicate with tubes 18, 20, respectively. Such orifices areillustratively 0.030-inch (0.08 cm) diameter and/or 0.040-inch (0.10 cm)diameter. Vacuum evacuating sub-system 66 cooperates with bandage 314,similar to bandage 14, to draw the fluid and exudate from the surface ofwound 300, and collect same into waste canister 26.

[0070] Examples of bandages 14 and 15 are shown in U.S. patentapplication Ser. No. 09/725,352, entitled VACUUM THERAPY AND CLEANSINGDRESSING FOR WOUNDS, filed on Nov. 29, 2000, and assigned to the sameAssignee or Affiliated Assignee as the present disclosure, and thecomplete disclosure of which is hereby expressly incorporated byreference. It is further contemplated that other bandages may be usedwith this control system, including bandages having separate irrigationand vacuum ports. Examples of such bandages are shown in U.S. patentapplication Ser. No. 09/369,113, entitled WOUND TREATMENT APPARATUS,filed on Aug. 5, 1999, and assigned to the same Assignee or AffiliatedAssignee as the present disclosure, and the complete disclosure of whichis hereby expressly incorporated by reference. The complete disclosureof U.S. patent application Ser. No. 10/144,504, entitled VACUUM THERAPYAND CLEANSING DRESSING FOR WOUNDS and filed on May 13, 2002, is herebyexpressly incorporated by reference.

[0071] A side diagrammatic view of bandage 14 along with a portion ofsystem 6 is shown in FIG. 9. (See also FIG. 1.) Bandage 14 is of anillustrative type for use with apparatus 2. (Note that the bandage isnot drawn to scale.) As previously discussed, bandage 14 is a vacuumbandage. Bandage 14 comprises a cover film 602, illustratively aflexible cover, that seals wound 300 about its outer perimeter. It iscontemplated, however, that film 602 can be made from an occlusive orsemi-occlusive material that allows water vapor to permeate therethrough, but otherwise protects wound 300 from the outside environment.A bandage member 604 is placed adjacent wound 300 and is configured toirrigate wound 300. In the illustrated embodiment, bandage member 604comprises upper channels 606 and lower channels 608, each provided onopposite sides 610, 612, respectively, of bandage member 604. Each ofthe upper channels 606 is generally congruent with one of the lowerchannels 608. Channels 606 and 608 are in communication with each othervia apertures 614. As shown in the illustrated embodiment, side 612 ofbandage member 604 faces wound 300, and side 610 faces a porous packing618. Packing 618 provided under film 602 to assist in providing a space616 to facilitate the negative pressure. Packing 618 is typically agauze material. It will be appreciated, however, that, for some woundcare applications, the packing 618 will not be used with member 604under the film 602.

[0072] Illustratively, the caregiver may activate system 6, by meanspreviously described, to draw exudate from wound 300 through channels606, 608 and apertures 614 of bandage member 604, packing 618 and film602, through splitter tube 620 connected to evacuating tube 20, anddeposit in canister 26. The negative pressure applied to wound 300created by pump 110 can be applied for a period of time as determined bythe caregiver. After a period of drawing, the caregiver may deactivatethe negative pressure. The caregiver may begin irrigating wound 300 byreleasing fluid from syringe 24, through tube 18, into splitter tube620, through film 602 and packing 618, and into bandage member 604. Thefluid will travel through channels 606 deposit in apertures 614 andirrigate wound 300 by traveling through channels 608. Illustratively,the fluid will continue to irrigate wound 300 until space 616 can nolonger receive any more fluid. The fluid is held in space 616 for aperiod of time as determined by the caregiver. After that period, pump110 is reactivated and the fluid and exudate from wound 300 is evacuatedfrom bandage 14 and into canister 26 by the manner previously described.This process is repeated as many times as necessary as determined by thecaregiver.

[0073] In one embodiment, user interface 10 comprises a momentary switch(not shown) that selectively operates the aforementioned process. Forexample, the switch may be configured such that when the caregiverdepresses and holds the switch, the fluid will dispense from syringe 24into bandage 14. When the caregiver releases the switch the fluid willstop dispensing and pump 110 will activate and begin drawing the fluidand exudate. It is contemplated that the switch may be configured todelay between the vacuuming and dispensing for a period of time that isdefinable by the caregiver. It is also contemplated that all of theaforementioned descriptions as applied to system 6 are applicable tosystem 8.

[0074] The apparatus 2 is a portable, easy to use topical system that isintended to provide a protective/occlusive environment with features tofacilitate the administering of standard wound care. The apparatus 2provides for the care of two independently controlled wounds. Theapparatus 2 provides negative pressure to the wound bed, and thecaregiver can set the level of negative pressure. Illustratively, thenegative pressure is variable from 25-mmHg to 175-mmHg at increments of10 mmHg. The caregiver can choose between continuous, intermittent(profile), and no negative pressure modes. It will be appreciated thatthe apparatus 2 may be set up to provide various levels of vacuum atvarious times. The apparatus may be provided with the ability to pausenegative pressure therapy for set durations of time. The system may beset up to provide audible alarms to remind the caregiver to reset orstart a new cycle of vacuum therapy.

[0075] The apparatus 2 is intended to provide an occlusive wound healingenvironment. The apparatus 2 provides an active therapy unit thatdelivers drainage and cleansing for aggressive wound healing. It isintended, for example, for use on all pressure ulcers (Stage II throughStage IV), surgical draining wounds and leg ulcers.

[0076] In the illustrated embodiment, as shown in FIGS. 7 and 10, forexample, canister 26 is configured to be received in cavity 9 disposedin side 38 of housing 4. As shown specifically in FIG. 10, cavity 9comprises two pull recesses 702, 704. Such recesses 702, 704 areconcave-shaped portions formed adjacent to side 38 and to side walls 706and 708. Recesses 702, 704 are provided to allow finger clearance whenthe caregiver grasps grip portions 39, 40 of canister 26 to remove itfrom, or insert it into cavity 9. (See also FIGS. 1, 11 and 13.) Sidewalls 706, 710 and bottom and top walls 708, 712 define cavity 9 suchthat cavity 9 provides a relatively conforming receptacle for thecanister 26. The walls 706, 710 and 708, 712 conform to the size andshape of the panels 714, 716, 718, 720 of canister 26. (See FIGS. 12 and13.) Outlet 412 of filter 108 mates with connector 416 to produce anair-tight seal between port 412 and connector 416. It is furthercontemplated that other structures or configurations of outlet 412 andconnector 416 can be used to ensure system 6 is a closed system whencanister 26 is properly coupled to housing 4. It is still furthercontemplated that the aforementioned descriptions of canister 26 ofsystem 6 apply equally to canister 27 of system 8.

[0077] Each of top and bottom panel 718, 720 of canister 26 includes aboss 722, 724, respectively. Each boss 722, 724 is configured to engagea sensor such as sensor 116, 118, respectively, as depicted in FIG. 2.This engagement provides a signal to controller 50 indicating thatcanister 26 is seated properly into cavity 9 and the vacuum therapytreatment may begin to be administered. It is contemplated that bosses722, 724 can be mechanical sensors, optical, capacitive or other similartype sensors.

[0078] Side panels 714, 716 include buttons 726, 728 to assist thecaregiver in placing canister 26 in the proper location within cavity 9.Illustratively, buttons 726, 728 are small protrusions, each extendingfrom a side panel. Each button 726, 728 is configured to be received or“snapped” into corresponding dimples 730, 732, respectively, disposed inwalls 706, 710, respectively. In the illustrated embodiment, the buttonsextend from the widest point of side panels 714, 716 of canister 26.

[0079] Another wound treatment apparatus 802 is illustrated in FIG. 14.Apparatus 802 is similar in structure and function to apparatus 2,except as otherwise noted, so that identical reference numbers refer tosimilar components. Apparatus 802 has a pair of vacuum wound bandages14, a pair of dispensing lines 18, a pair of evacuating lines 20, and amain control unit 803 adapted for use with bandages 14 and lines 18, 20.Bandages 14, lines 18, 20, and control unit 803 cooperate to providedual vacuum therapy systems 806, 808.

[0080] Control unit 803 has a control module 810, a pair of fluidsources such as syringes 24 coupled to dispensing lines 18 to providefluid for irrigation of the wounds, and a pair of disposable wastecollection canisters 826 coupled to evacuating lines 20 to collect wastematerial such as exudate from the wounds and fluid from syringes 24, asillustrated in FIG. 14. Each dispensing line 18 and evacuating line 20is associated with one of bandages 14. Each syringe 24 and canister 826is provided for one of systems 806, 808. Control module 810 has ahousing 804. Syringes 24 are coupled to the front of housing 804 andcanisters 826 are coupled to the sides of housing 804, as discussed inmore detail below. Housing 804 has a handle 812 at the top thereof forhand-carrying control unit 803. A user interface 10 is centrally mountedto housing 804 between syringes 24 and canisters 826 to allow acaregiver to operate systems 806, 808.

[0081] Systems 806, 808 are similar to one another in structure andfunction. Thus, the following description of system 806 applies also tosystem 808.

[0082] Housing 804 has a door 832 to partially cover syringe 24, asillustrated in FIG. 14. Door 832 is hinged to housing 804 by a pair ofvertically-spaced hinges 814 positioned along a laterally outer side 815of door 832 for movement of door 832 between opened and closedpositions. A rear side 816 of door 832 has a plurality ofvertically-spaced, horizontal mounts or grooves 817 (see FIGS. 14 and17) for receiving a flange 818 of syringe 24. Housing 804 also has aplurality of corresponding vertically-spaced, horizontal mounts orgrooves 820 (see FIGS. 14 and 17) for receiving flange 818. Duringinstallation of syringe 24, an end of a plunger 70 of syringe 24 isplaced on a vertically movable plunger interface 78 of a syringe drivemechanism, such as the one described above in connection with apparatus2, and flange 818 is inserted into one of grooves 820. Door 832 is thenclosed causing one of grooves 817 to receive flange 818 so that syringe24 is held in place by grooves 817, 820. Grooves 817, 820 supportsyringe 24 in a vertical orientation.

[0083] A door latch 822 is coupled to a laterally inner side 824 of door832, as illustrated in FIGS. 14-16. Latch 822 is movable relative todoor 832 between a latched position (FIG. 16) blocking movement of door832 from its closed position to its opened position and a releaseposition (FIGS. 14-15) allowing door 832 to move between its closedposition and its opened position. Latch 822 has a fastener 828, such asan arm or lug, and an actuator 830 to pivot fastener 828 into and out ofa slot 834 of housing 804 between the latched and release positions.Actuator 830 has a stem 836 coupled to fastener 828 and a handle or doorknob 838 coupled to stem 836 to rotate stem 836 and thus fastener 828between the latched and release positions when a caregiver rotateshandle 838. Stem 836 extends through an aperture of door 832. Handle 838is coupled to one end of stem 836 in front of door 832 and fastener 828is coupled to an opposite end of stem 836 behind door 832.

[0084] Canister 826 is coupled to vacuum bandage 14 and other componentsof apparatus 802, as illustrated, for example, in FIG. 27. Evacuatingline 20 is coupled to vacuum bandage 14 and an inlet port 850 ofcanister 826 to introduce waste material into an interior region orchamber 866 of canister 826 through inlet port 850. A pressure sensor124 is coupled to an upper pressure port 852 of canister 826 via a fluidline 854 (see FIGS. 19 and 27) to sense the pressure in region 866.Pressure sensor 124 sends a signal indicative of the sensed pressure toa controller 850, which is common to both systems 806, 808, via anelectrical line 856 (see FIG. 27). A proportional valve 130 (see FIGS.19 and 27) is coupled to a lower outlet port 857 of canister 826 via afluid line 858 (see FIGS. 19 and 27). A pressure regulator 134 (seeFIGS. 19 and 27) is coupled to proportional valve 130 and a vacuumsource 110 (see FIGS. 19 and 27) via fluid lines 860 and 862,respectively (see FIG. 27). Vacuum source 110 provides a negative orvacuum pressure within bandage 14 through lines 862, 860, 858, 20 andregulator 134, valve 130, and canister 826 to suction waste materialinto canister 826.

[0085] Vacuum source 110 continues to operate even if, for example,blockage occurs somewhere upstream from vacuum source 110. If theblockage becomes too great, vacuum source 110 could experience too greata load, or vacuum pressure. Pressure regulator 134 is provided toestablish a maximum load that vacuum source 110 can experience. Pressureregulator 134 allows air to be suctioned into line 862 when this maximumload is reached to protect vacuum source 110.

[0086] A filter 864 is positioned in interior region 866, as shown inFIGS. 20, 23, and 27. Filter 864 covers pressure port 852 and outletport 857 to prevent waste material from entering lines 856, 858 andpossibly damaging pressure sensor 124, proportional valve 130, pressureregulator 134, or vacuum source 110. Filter 864 is, for example, a 1.0micron teflon hydrophobic filter.

[0087] Controller 850, pressure sensor 124, and proportional valve 130cooperate to provide feedback control of the vacuum pressure provided tobandage 14. Controller 850 operates proportional valve 130 viaelectrical line 864 in response to the pressure sensed by pressuresensor 124 to provide a desired negative pressure in interior region866. A caregiver provides the desired negative pressure to controller850 through user interface 10. If, for example, pressure sensor 124senses a pressure in canister 826 that is more negative than the desirednegative pressure (which includes a suitable tolerance range),controller 850 will cause valve 130 to move closer toward its fullyclosed position so that interior region 866 experiences less of thesuction from vacuum source 110 and the pressure in canister 826 rises toapproach the desired negative pressure. On the other hand, if pressuresensor 124 sense a pressure in canister 826 that is more positive thanthe desired negative pressure, controller 850 will cause valve 130 tomove closer to its fully opened position so that interior region 866experiences more of the suction from vacuum source 110 and the pressurein canister 826 lowers to approach the desired negative pressure.

[0088] Based on readings from pressure sensor 124, controller 850 isable to detect when the waste material in canister 826 has reached afill limit, which occurs when the waste material at least partiallyoccludes outlet port 857. As outlet port 857 becomes occluded due to thewetting of filter 864, the negative pressure established by vacuumsource 110 becomes blocked from interior region 866. The pressure sensedby sensor 124 then begins to rise (i.e., become less negative) above thedesired negative pressure, especially if bandage 14 has a vent incommunication with atmosphere, and air enters interior region 866through bandage 14, line 20, and inlet port 850. In some embodiments,air enters interior region 866 through a bleed port (not shown) formedin housing 884 at an elevation higher than outlet port 857 instead ofthrough the bandage vent or in addition to the bandage vent. In responseto the pressure rise, controller 850 moves proportional valve 130 towardits fully opened position to try to lower the sensed pressure to thedesired negative pressure. If vacuum source 110 is able to lower thesensed pressure to the desired negative pressure, the waste materialfill limit has not been reached. If the sensed pressure remains abovethe desired negative pressure, controller 850 opens proportional valve130 further and compares the sensed pressure to the desired negativepressure.

[0089] Controller 850 determines that the waste material in canister 826has reached its fill limit when proportional valve 130 has been fullyopened but the sensed pressure remains above the desired negativepressure. This occurs because the waste material has occluded outletport 857 enough to prevent vacuum source 110 from being able to lowerthe sensed pressure to the desired negative pressure. Pressure sensor124, however, is still able to sense the pressure within interior region866 through pressure port 852 because pressure port 852 is positioned atan elevation higher than outlet port 857. Controller 850 then activatesan alarm 868 via an electrical line 870 to alert a caregiver thatcanister 826 is full and needs to be changed.

[0090] Housing 804 contains components of control unit 803, asillustrated in FIG. 19. Housing 804 has two receptacles 840, onereceptacle 840 on each side of housing 804, and each receptacle 840 isconfigured to receive a respective canister 826 therein. Housing 804also has a removable vertical rear wall 842 (see FIG. 18). Behind rearwall 842 is a chamber 871 (see FIG. 19). Each receptacle 840 extendstoward a center of chamber 871 from a side wall of housing 804. Aprinted circuit board (PCB) 872 is mounted to a rear surface of a frontwall 873 of housing 804 within chamber 871. Pressure sensors 124 andcontroller 850 are mounted to PCB 872 within chamber 871. Valves 130,pressure regulators 134, vacuum sources 110, and lines 854, 858 are alsopositioned within chamber 871.

[0091] A pair of mufflers 874 and a pair of muffler lines 876 arepositioned within chamber 871. Each muffler line 876 is coupled to oneof mufflers 874 and one of vacuum sources 110. Illustratively, eachmuffler 874 has three disk filters 878 in series to provide threechambers 880 having glass fiber material 882 therein to absorb soundenergy. Adjacent filters 878 are coupled together by luer-lockmechanisms.

[0092] A battery 954 rests on a bottom wall 956 of housing 804 inchamber 871, as illustrated in FIG. 19. A main power connection 958 iscoupled to battery 954 and to PCB 872. Battery 954 is illustratively arechargeable nickel metal hydride battery that automatically rechargeswhen main power connection 958 is coupled to an external electricaloutlet (not shown) via a power cord (not shown), for example, andautomatically provides electrical power to the electrical components ofcontrol unit 803 when battery 954 is charged and the power cord isdisconnected from the external electrical outlet.

[0093] A mounting bracket 844 is coupled to an outwardly facing surfaceof rear wall 842, as illustrated in FIG. 18, to mount control unit 803to a suitable control unit support (not shown). Bracket 844 has anenvelope 846 to receive the support through a lower opening 848. Ahorizontal upper wall 849 is coupled to the top of envelope 846.Envelope 846 has internal tapered walls 960 extending from the bottom ofenvelope 846 to upper wall 849. The control unit support wedges againsttapered walls 960 when it is inserted within envelope 846.

[0094] Canister 826 has a housing 884 providing interior region 866 tocollect waste material therein and a latch 886 to couple housing 884 tohousing 804 of control module 810, as illustrated in FIGS. 14 and 20-23.Canister 826 further has a cylindrical sleeve 888 carried by housing 884and extending horizontally through interior region 866. Ends of sleeve888 are appended to respective outer and inner vertical walls 891, 899of housing 884. Walls 891, 899 are each formed with an aperture 889 thatcommunicates with an interior region of sleeve 888. Latch 886 extendsthrough apertures 889 and sleeve 888 and engages a vertical back wall890 of receptacle 840, as described in more detail below.

[0095] Outer vertical wall 891 of housing 884 and sleeve 888 cooperateto provide a monolithic unit that is coupled, such as by RF orultrasonic welding or adhesive, to a main portion 892 of housing 884(see FIGS. 20-23). An outer end portion 893 of sleeve 888 is formedmonolithically with a recessed portion 894 of wall 891. Wall 891 has aperipheral flange 895 that is coupled to a corresponding peripheralflange 896 of main portion 892. An inner end portion 897 of sleeve 888is coupled to a recessed portion 898 of inner vertical wall 899 of mainportion 892. Outer wall 891 has inlet port 850 formed integrallytherewith or appended thereto. Inner wall 899 has upper pressure port852 and lower outlet port 857 formed integrally therewith or appendedthereto.

[0096] Latch 886 has a fastener 910 to couple to back wall 890 and anactuator 912 to rotate fastener 910, as illustrated in FIGS. 21-23.Fastener 910 has a pair of bayonet-style canted lugs 914 coupled to aninner end portion 916 of a shaft 918 of actuator 912. Lugs 914 arediametrically opposed to one another and extend somewhatcircumferentially and axially on shaft 918.

[0097] Actuator 912 further has a handle 920 coupled to an outer endportion 922 of shaft 918, as illustrated in FIGS. 14, 20, 22 and 23.Handle has a disk 924 coupled to end portion 922 and a flange 926coupled to and extending radially outwardly from disk 924. Disk 924 anda portion of flange 926 are positioned within recessed portion 894.Recessed portion 894 has a pair of stop edges 952 (see FIG. 20)positioned to restrict rotation of flange 926 to about 90 degrees.

[0098] A retainer 928 (see FIGS. 21-23) is mounted to shaft 918 betweenhandle 920 and fastener 910. Illustrative retainer 928 has a clip 930,such as an e-clip, and a clip mount 932. Clip mount 932 takes the formof a disk mounted to shaft 918 and has a circumferential groove 934configured to receive clip 930. Disk 932 has a diameter smaller than theinner diameter of sleeve 888 to facilitate insertion of fastener 910through sleeve 888 during assembly of canister 826. After insertion offastener 910 through sleeve 888, clip 930 is positioned in groove 934 toengage recessed portion 898 to prevent latch 886 from inadvertentlywithdrawing from sleeve 888. An inner portion of disk 932 is received inone of apertures 889 and disk 924 is received in a space defined by anarcuate edge 950 (see FIGS. 20, 22, and 23) of wall 891 to support latch886 for rotation relative to housing 884.

[0099] After latch 886 is coupled to housing 884, canister 826 is readyto be installed within receptacle 840. A caregiver places canister 826within receptacle 840 (see FIG. 22) and inserts leading edges of lugs914 through an aperture 938 of back wall 890 shaped to receive lugs 914(see FIG. 24). The caregiver then rotates handle 920, and thus lugs 914,by hand, for example, approximately 90 degrees in a direction 936 (seeFIG. 25). This rotation causes lugs 914 to cam against inwardly facingthrust surfaces 940 of back wall 890 (see FIG. 26) SO that canister 826moves toward back wall 890 and pressure port 852 and outlet port 857 aredrawn into corresponding upper 904 and lower 906 sockets, respectively,of back wall 890 (see FIGS. 22-23). Each port 852, 857 has a nipple 900that is inserted into the respective socket 904, 906 and an O-ring 902surrounding nipple 900. When lugs 914 are rotated against surfaces 940,nipples 900 are drawn into sockets 904, 906 SO that O-rings 902sealingly engage tapered walls 908 of sockets 904, 906. Sockets 904, 906provide portions of lines 854, 858, respectively. A dome cover 942 ispositioned on an inner surface of back wall 890 and over lugs 914 andinner end portion 916 of shaft 918.

[0100] Canister 826 is removed from receptacle 840 and disposed of whencanister 826 is full of waste material. To do so, a caregiver removesline 20 from inlet port 850, places a cap (not shown) on port 850 toprevent spillage, and rotates handle 920 in a reverse direction 944 torelease lugs 914 from back wall 890. The caregiver then pulls on sidegrips 946 (see FIG. 14) of canister 826 to remove canister 826 fromreceptacle 840. As canister 826 is removed from receptacle 840, lugs 914pass back through aperture 938 and pressure port 852 and outlet port 857are withdrawn from upper and lower sockets 904, 906. Canister 826 canthen be discarded and a new, empty canister 826 can be installed withinreceptacle 840.

[0101] By having latch 886 included as part of canister 826, which isdisposed of after being filled with waste material, latch 886 is notused over and over again, thereby preventing lugs 914 from wearing downand degrading the sealed connection between ports 852, 857 and sockets904, 906.

[0102] Although the foregoing apparatus has been described, one skilledin the art can easily ascertain the essential characteristics of theapparatus, and various changes and modifications may be made to adaptthe various uses and characteristics without departing from the spiritand scope of this disclosure, as described by the claims which follow.

What is claimed is:
 1. A control unit adapted for use with a vacuumwound bandage, the control unit comprising a control module to provide anegative pressure through the vacuum wound bandage, a canister having aninterior region to collect waste material from the vacuum wound bandageand a latch to couple the canister to the control module, the latchextending through the interior region.
 2. The control unit of claim 1,wherein the canister has a sleeve positioned within the interior region,and a portion of the latch is positioned within the sleeve.
 3. Thecontrol unit of claim 2, wherein the canister has a first wall and asecond wall, and the sleeve extends from the first wall to the secondwall.
 4. The control unit of claim 2, wherein the latch has a shaftpositioned within the sleeve.
 5. The control unit of claim 1, whereinthe canister has a first wall having a first aperture and a second wallhaving a second aperture, the control module has a third wall having athird aperture, and the latch extends through the first aperture, thesecond aperture, and the third aperture.
 6. The control unit of claim 1,wherein the latch has an actuator and a fastener to couple the canisterto the control module in response to rotation of the actuator.
 7. Thecanister of claim 6, wherein the control module has a housing, and thefastener has a pair of canted lugs to cam against the housing of thecontrol module in response to rotation of the actuator.
 8. The canisterof claim 7, wherein the housing of the control module has an aperture,and the canted lugs pass through the aperture when the canister iscoupled to the control module.
 9. The control unit of claim 6, whereinthe actuator has a shaft coupled to the fastener and positioned withinthe interior region.
 10. The control unit of claim 9, wherein theactuator has a handle coupled to the shaft to rotate the fastener. 11.The control unit of claim 1, wherein the control module has a housing,the canister has a housing having the interior region, and the latch isoperable to move the housing of the canister into sealing engagementwith the housing of the control module.
 12. The control unit of claim11, wherein the housing of the canister has a port, the housing of thecontrol module has a tapered socket, and rotation of the latch againstthe housing of the control module draws the port into the tapered socketto provide the sealing engagement between the housing of the canisterand the housing of the control module.
 13. A canister adapted for usewith a vacuum wound bandage associated with a wound of a patient and acontrol module to provide a negative pressure through the vacuum woundbandage to treat the wound, the canister comprising a housing having aninterior region to collect waste material from the vacuum wound bandage,and a latch to couple the housing to the control module, the latchextending through the interior region.
 14. The canister of claim 13,further comprising a sleeve carried by the housing and positioned withinthe interior region, and a portion of the latch is positioned within thesleeve.
 15. The canister of claim 14, wherein the housing has a firstvertical wall and a second vertical wall, and the sleeve extends fromthe first vertical wall to the second vertical wall.
 16. The canister ofclaim 15, wherein the first vertical wall has a first recessed portion,the second vertical wall has a second recessed portion, and the sleevehas a first end portion coupled to the first recessed portion and asecond end portion coupled to the second recessed portion.
 17. Thecanister of claim 16, wherein the latch has a handle positioned forrotation within the first recessed portion and a retainer to engage thesecond recessed portion to maintain the latch within the sleeve.
 18. Thecanister of claim 16, wherein the first recessed portion is configuredto limit rotation of the handle to about 90 degrees.
 19. The canister ofclaim 15, wherein the first vertical wall has an inlet port to introducewaste material from the vacuum wound bandage into the interior region,the second vertical wall has an outlet port to communicate with a vacuumsource of the control module, and the sleeve is lower than the inletport and the outlet port.
 20. The canister of claim 13, wherein thehousing has a first wall having a first aperture and a second wallhaving a second aperture, and the latch extends through the firstaperture and the second aperture.
 21. The canister of claim 13, whereinthe latch has an actuator and a fastener to couple the housing to thecontrol module in response to rotation of the actuator.
 22. The canisterof claim 21, wherein the fastener has a pair of canted lugs to camagainst the control module in response to rotation of the actuator. 23.The canister of claim 21, wherein the actuator has a shaft coupled tothe fastener and positioned within the interior region.
 24. The canisterof claim 23, wherein the latch has a retainer coupled to the shaft tomaintain the shaft within the interior region.
 25. The canister of claim24, wherein the retainer has a clip and a disk having a groove, and theclip is positioned within the groove to engage the housing.
 26. Thecanister of claim 23, wherein the actuator has a handle coupled to theshaft to rotate the fastener.
 27. A control unit adapted for use with avacuum wound bandage, the control unit comprising a vacuum source toprovide a desired negative pressure through the vacuum wound bandage, apressure sensor, and a canister having a chamber to collect wastematerial from the vacuum wound bandage, an inlet port to introduce wastematerial from the vacuum wound bandage into the chamber, an outlet portto communicate with the chamber and the vacuum source, and a pressureport to communicate with the chamber and the pressure sensor, thepressure port being positioned to allow the pressure sensor to sense thepressure within the chamber when the waste material within the chamberat least partially occludes the outlet port so as to prohibit the vacuumsource from providing the desired negative pressure within the chamber.28. The control unit of claim 27, wherein the pressure port ispositioned at an elevation higher than the outlet port.
 29. The controlunit of claim 27, wherein the canister has a vertical wall, and thevertical wall has the outlet port and the pressure port.
 30. The controlunit of claim 27, wherein the canister has a filter covering the outletport and the pressure port.
 31. The control unit of claim 27, furthercomprising a lower socket and an upper socket, the outlet port ispositioned within the lower socket, and the pressure port is positionedwithin the upper socket.
 32. The control unit of claim 27, furthercomprising a controller coupled to the pressure sensor and aproportional valve coupled to the controller, the proportional valvebeing positioned fluidly between the vacuum source and the outlet port,the controller being configured to operate the proportional valve inresponse to the pressure sensed by the pressure sensor to provide thedesired negative pressure within the chamber.
 33. The control unit ofclaim 32, further comprising an alarm coupled to the controller, thecontroller being configured to activate the alarm when the proportionalvalve is fully open and the pressure sensor senses that the pressurewithin the chamber is greater than the desired negative pressure due toat least partial occlusion of the outlet port by waste material withinthe chamber.
 34. A canister adapted for use with a vacuum wound bandage,a vacuum source that provides a desired negative pressure through thevacuum wound bandage, and a pressure sensor, the canister comprising achamber to collect waste material from the vacuum wound bandage, aninlet port to introduce waste material from the vacuum wound bandageinto the chamber, an outlet port to communicate with the chamber and thevacuum source, and a pressure port to communicate with the chamber andthe pressure sensor, the pressure port being positioned to allow thepressure sensor to sense the pressure within the chamber when the wastematerial within the chamber at least partially occludes the outlet portso as to prohibit the vacuum source from providing the desired negativepressure within the chamber.
 35. The canister of claim 34, wherein thepressure port is positioned at an elevation higher than the outlet port.36. The canister of claim 34, wherein the canister has a vertical wall,and the vertical wall has the outlet port and the pressure port.
 37. Thecanister of claim 34, wherein the canister has a filter covering theoutlet port and the pressure port.
 38. A control unit adapted for usewith a vacuum wound bandage associated with a wound of a patient, thecontrol unit comprising a vacuum source to provide a negative pressurethrough the vacuum wound bandage, a fluid source to irrigate the wound,a housing carrying the vacuum source and the fluid source, a doormovable relative to the housing between an opened position uncoveringthe fluid source and a closed position at least partially covering thefluid source, and a latch coupled to the door for movement relative tothe door between a latched position blocking movement of the door fromits closed position to its opened position and a release positionallowing the door to move between its closed position and its openedposition.
 39. The control unit of claim 38, wherein the housing has aslot, and the latch is positioned within the slot in the latchedposition and outside the slot in the release position.
 40. The controlunit of claim 39, wherein the latch has a fastener and an actuator torotate the fastener into and out of the slot.
 41. The control unit ofclaim 40, wherein the actuator has a handle positioned in front of thedoor, and the fastener is positioned behind the door.
 42. The controlunit of claim 41, wherein the actuator has a stem coupled to the handleand the fastener and extending through the door.
 43. The control unit ofclaim 42, wherein the fastener is an arm perpendicular to the stem. 44.The control unit of claim 38, wherein the door has a first side and asecond side, the first side is hinged to the housing, and the latch isrotatably coupled to the second side.
 45. A control unit adapted for usewith a vacuum wound bandage associated with a wound of a patient, thecontrol unit comprising a vacuum source to provide a negative pressurethrough the vacuum wound bandage, a fluid source to irrigate the wound,a housing carrying the vacuum source and the fluid source, and a doorcoupled to the housing and at least partially covering the fluid source,the door having a mount supporting the fluid source.
 46. The controlunit of claim 45, wherein the mount is a groove, and the fluid source isa syringe having a flange positioned within the groove.
 47. The controlunit of claim 46, wherein the door has a plurality of vertically-spacedgrooves, and the flange is positioned within one of the grooves.
 48. Thecontrol unit of claim 47, wherein the housing has a plurality ofvertically-spaced grooves, and the flange is positioned within one ofthe grooves of the housing.
 49. The control unit of claim 46, whereinthe housing has a groove, and the flange is positioned within the grooveof the housing.
 50. The control unit of claim 49, wherein the groovesare horizontal so that the syringe is oriented vertically.